Multiplex-telegraph system.



' ,1. E. 11. 110GB. MULTIPLEX TBL EGBIAPH SYSTBNL i113 APR.11,11910.

APPLIOATION r11.

Patented Noir. 11, 1913.

6 SHEETS-SEBBT l.

aulo l J. P. D. HOGE.

MULTIPLBX TELBGRAPH SYSTEM. APPLIOATION FILED APR.11, 1910,

' Patented Nov. 11, 1913.

In ventor f 'by l. -1 -ffmy J.. F. D. HOGE.

MULTIPLEX TELBGRAPH SYSTEM.

APPLICATION FILED APR.11, 1910.

1,078284. Patented Nov. 11, 1913.

6 SHEETS-SHEET 3.

J. F. D. HOGE.

MULTIPLEX TELBGRAPH SYSTEM.

APPLxoATIoN rmzv APR. u. 1910.

1,078,284. Patented Nov. 11, 1913.

J. F. D. HOGE. r MULTIPLBX TELEGRAPH SYSTEM.

APPLICATION FILED APR. l11l 1910.

Patented Nov. 11, 1913.

Juanan-lion y @foi tu@ on e o m A94., @35u @Hob 1l; A v

J. P. D. HOGE. MULTIPLEX TELGRAPH SYSTEM. APPLICATION FILED APR.11,1910.

6 SHEETS--SHEBT 6.

strenge yruns? 1 its JOSEPH F. D. -HOGE,VOF NEW YORK, N. Y., ASSIGNOR TO AMERICAN DISTRICT TELEGRAPH GMPANY, A CORPORATION 0F NE'W JERSEY.

MULTIPIiEX-TELEGRAPH SYSTEM.

interese.

To all zo/om moy concern.'

Be it known that l, JosnPirF. Dfloen, s citizen of the United States, residing A:it New York, in the county or' New` York end Stets I of New York, have invented e certeinnew and useful Multiplex-'Telegraph System, of

sense, the equivalent, in s system such as herein described, of district, messenger callboxes) and will then point out certain applicstions of my invention in connection 7with ordinary telegraphy.

lndistrict messenger systems, fire clarin systems, and the lil c, it customary to provide u nuinbcr of call boxes in a single circuit, these boxes adapted each. to transmit n signal (usually e number) diierent from the signals ofthe other boxes in the suine circuit, suitable receiving devices being'located at what for convenience niuy be termed aiy central station In practice there are a. number of such circuits leading' to the ,su-ine central station, and the call boxes or transmitting' devices of each circuit nre usually somewhat close together; There is u practical limit to the number of boxes that nitty be placed in any one circuit., and give goed service, this nninhervarying more or less o cording to local conditions, but since/in gen- ,ersl any such systeml will comprise circuit conductors ot considerable length leading from the central station tothe vicinity Where the boxes nre located; a considerable economy may be effected if these sume conductors may be used ior transmitting the vsignals of an entirely distinct group of boxes` provided no interference between the signals ot the different gcups of boites results. This l accomplish according` to my present invention. v arrange to inniose upon the saine circuit conductors two distinct cnrrents, one s direct current, the other :inalternuting current of somewhat high lre- Specification of Letters Patent. Application lecl April 11,. 19143'. :Serial No. 554,668.

q uency, and provide two groups of call boxes, one arranged to aect the direct cnrrent, the y other to affect the alternatinig,r current; end'. l provide two clistinct receiving devices, one ior the direct current signals, the other for the alternating Vcurrent signals. direct current boxes and. the line conductors, end between the direct current receiving; de vices and `the .line conductors, l Aprovide ineens for pre-venting these instruments,

nating' current t-ransiniitin;r und receiving' devices, l term, for the salte of* a naine, phantom circuits. In like manner I may iniypcse two or-more alternating currents upon the sume circuit, with Without un additional direct current, es desired; the

alternating currents beingof ciflerent fre-- qnencies; und I sepa-rate the alternating currents one from another, operatively, by elnploving suitable condensers and inductance coils.

My invention therefore comprises a plurality ci' signaling systems, employing' the sinne linc conductors, oneor more of said systems operating by ineens of alternatingT .f-urrents, together with nicuns for isolating; the several systcn'is. cach from ill of the others; also e plurality of signaling; systems employing the sonic line conductors, one of said systems operating by direct current.v the other or others by alternating' currents, to-' Igcther with ineens for isolating` the rseveral v systems'erich troni all the others; 'also vari ons other features hereinafter described :indv pointed out in the appended vcla-ilus.

ATh'el isolation of the several s-v tenis einiiloying the suine line conductors, sccording to my invention, depends (first) on the fact that on' induclunce coil can be constructed which for any given conditions will limit the passage of an alternating current through ,it to env desired ,vslue,,however small ententes-Nenn,-ieis.

Between the (though in practice such inductance coil cannot be made to actually exclude the alterhating currentaltogether, but can be made to limit it to such value that it does not cause disturbance of the instruments); (second) on the fact that a condenser' and an inductance coil placed in series in a circuit, may have the values of their capacity and inductance, respectively, so chosen, thatl they will have a very small impedance. to an alternating` current of a given frequency,

but will offer a great impedance to one o-f-a higher or lou-'er frequency, the condenser being efl'ective principally to exclude curdirect current from the alternating current system or systems, is somewhat similar to eX- cluding an alternating current of lower frcquency from systems in which alternating currents of higher 'frequency are used, for while a condenser will pass no current for a constant direct potential aft-er once charged,

l a pulsating direct current will give rise to an alternating current through the con` denser, the condenser' accepting current in one direction to charge it as the potential v rises, and passing it in the opposite direction by discharging as the potential falls.

The objects of my invention are to ih crease 'the' service capacity of telegraph, alarm, and other signaling circuits and the like, without detriment tcthe service given, to avoid conflict between the several superimposed signaling systems, to maire the apparatus required simple, ca-Xy unilcrstood, easily adjusted, and relatively inexpensive, to make the complete system operate correctly either over a metallic circuit or over ground return circuits, and to provide for the conversion at will of a metallic circuit system into tw) independent ground return systems, and vi .'e versa, and to make' the system as a whole ,operative with currents of l low potential and with instruments of a'simpleand relatively inexpensive type.

l will now proceed to describe my invention with reference to the accompanying drawings, illustrating more or diagrammatic-ally different arrangements of circuits and instruments embodying my invention.

In said drawings Figure l shows diagrammatically a call. box system comprising a. direct current side. and an alternating current'side, using the same line conductors and operating normally through. metallic circuit but adapted at will to be changed into twoseparate systems con'iprising each a linev conductor and a ground return; Fig. 2 illustrates an alternating system in general similar to that of Fig. 1 but employing rectifers on the alternating current side in connection with the receiving relay of the alternatg -ing current side; Fig. 3- is a view similar'to Fig. l, but illustrates the use of a'plurality Fig. 6 shows a front elevation of said rela Fig. 7 shows a detail elevation vof the yo e supportinggthe Contact stops between which the armature plays; Fig. 8 shows a front elevation'of an alternative form of relay; Fig. 9 is a detail side elevation of the lower portion of the armature, the paddle, and the liquid' containing cup of that relay;- F ig. 10 is a diagram illustrating one application of my in- `vention in ordinary telegraphy; Figs. 11 and l2 are similar views illustrating other applications of my invention in ordinary telegraphy; and Fig. is a diagram illustrating one method of duplexing alternatingcurrent systems such as herein described. v

Referring now to the drawings, and at first to Fig. l, 1 and 2 designate line conductors, serving both for the primary signaling circuit and for the phantom circuit, before referred to.

3, 3 designate ordinary `call boxes, z'. e., signaltransmitters, .in a primary circuit 4 connected to the line conductors ll and 2 through inductive resistances 5; and G des'- ignates a corresponding direct current lreceiving set, at a central station, connected to line conductors` l and 2 through inductive resistances 7. The call boxes 3 yare to be understood to be of any well known type i and for ordinary call, signal, or alarm service are preferably arranged to work accord ing vto the well-known McGulloh' vsystenn each having, as is customary in such boxes,

two signal wheels of simil-ail signal nu1nbers,.

one arranged to work `through the metallic circuit,'the other to work through a ground return, each such box having a ground connection 8. The receiving set 6 is. ofthe general nature of such sets as commonly employed in district telegraph work, comprising receiving relays 9 and l0, (in this system usually having resistance of, from to 1000 ohms) a receiving register l1, and a further 'receiving device l2, also adoublethrow multi-pole s itch 13, commonly termed a McCulloh switch in a'system such.

as this, by which the circuit comprising con- Lorenzi@ dueors i. sind 2 may he con'rerte, et Wiil, into two seperate grounciretizrn circuits, aooordinm o the Well-imown llfolulloh system. The generali arrangement ot the instrimfzentI 5 oi the receiving set 6, shown inthe drawings, is that of the potent to Hambiin 808,451, dated Dee. 26, 1905.

le designates e direct-current generator, ei another direcoonrrent generator supplying current to the iocel. oireuit oi receiving sets 6 and 2G, and 15, j suitable non-inductive resistenoes of from 2o@ to 300 ohms-iu any ease, e resistance high enough to make resistance, rather than iiidiiotenee, the ,oontroliing friet-or in the ioeel Circuits of the di1eot-e-irrent receiving set 8. Gtherwise, the indiie'trince of the loeei direet-current reeeiving apparatus would deiiy the current rise and fell end vso prevent it .responding to impulses short duration in the'desired manner.

, l5 designate eallhoees similar to boxes 3, but located in av t phantom circuit 17 oon` neoted to eonduotors l Aend 2 respectively, through condens/ers 1S, and inductive re 'stances 19.v

E2G is e, receiving set, for boxes it, arranged to be operated by alternating currents of relatively high zequeney, and connected to conductors l sind 2 through eondei'isers and inductive resist-ences 2% designates an alternating current generator for suppiying current to receiving set 20 end hores 16. Receiving set E20 is in geng eral the same es set (i, comprising fmt 'e register 25, another signal re ing devise 27, sind e doublerhrow inuit, p Mo'Cuiloh switch 28, by which the i tom Circuit; 17, the current o't which i" superimposed upon the direct current o cir- Guit owing throi ffii. conductors l and E2 me? he eonvertefi, will, into two seperate ii-rideetiirn circuits, according to the hewn szofuiioii system.

rou-nd practically nearly impossihie to teorie: ordinary direot---onrreet relays I'on alterne thigenrrents of the requeneies which I pro-wee tense in i yet in, Withoutfemes herein1 5, if operated '9W eheh currents, do not produc soiiioiently goed contacts between their er' tures and trent Contact in, nts, owing to wie eonsteiit alternate simg'netizetion and denzignetine tio-1i ot' their magnets and the eo" int pull, 'upon their :irrimtiires o the eiisoniery ormew titre retraotiie springs; `he'nee i preferahiy employ, for relays 24 and 25, relays of the special. type hereinafter deserihed end illus tinted in Figs. 4-9 inclusive, which een he adjusted to be opereteol hy an yelteriating; oiiireiit o t "nite freeneney', es positive@ relief; 'een he operated h5* 4ou rent. v Frei T15, 'ere ,provided with poyi-iig specie?. adept g me after described, lsince srieh rei the hand switches usually provided in relays, ot the MeCulloh type, end described in the E einhlin patent referred to, for use in Cheng ing from metallic circuit to independent ground-return circuits. The use and eii'ectv oit such switches being described in said petenti, in connection with switches oorresponding to switches' 13 and 28 herein, need not be described here. l

Sinee inductive resistences, such es coiis 5 and 7, oiier only ohmie resistance to direct currents, but offer Very much greater resietenee to alternating and pulsatory currents, and since condensers, such es 18 and 21., are opaque to direct current, .but transparent to alternatingeuirents, it is practicable, by employing inductive resistenoes 5 and T of su'iiicient retardation, and by employing condensers 18 end' '21, to Vcom?l pieteiy isolate, operatively, the primzirygor direct-ennemi; eironit, 4, and its receiving set 6, from the phantom circuit 17, and its receiving set, 20, notwithstanding that 00th circuits endlooth receiving sets use the same line Conductors l, 2 and ground.

in l the switches 13 and 28jare indicated as in the position for normal Working, that is to say, for working with a complete niet-allie eirenit. in this eri; it; is customary to speak of suo-h e system as Working non nielly when working on e foonipiete .momilie circuit, anelito Spee-k ott the system as Working as e liioluiohsystein, or, is the phrase is, Working ivoulhih, 'Wi'ien the system is Working with groei-iti return fairen-its.

A large. non-inductive r i'etenoe Tl() (say o, resistance of about 700'() Iehr-ns) is provided in the main eirenit in order that folie impedence oef? the line l z-oinpoeed largely et' resistanee, the oe ofi the line itself, in a system snee ilinstreted herein, he ing nsueliy not Tregiter than' i-:OQO ohms. This eiiahles ehe reieys to 4lleep pace 'with rapid signels, afin-fi as the values loi? :the line Currenti'neii, this does ieee power. 5513 were .n the l' the switch 13, :the dire-e ni is eeueod to operate i syezerm.,f :i practical, i. he presented, since-fin suoli omv fl Ireturn circuits et Vdieset te, .produoedhy reveising the switch i from the 'position sh ...n in iiig. would eeeh cont-ein iess resistance than .the meteiiio eii'oiiit used in iori'nzil operation, for he inetellio circuit cori.

inshoth relays 9 and i9, -esieh of large resistance, Whereas the two ground return ensuite, When'the system is operst' es e MeG-nlloh system, ezieli ooniiii-ns hui, these relays. rThis ohenge foi resistance, when converting -the dirent -oerrrent frntotwo, ground ret, voironits., it' 'not oetintefrootefi,i would sense -tliegeiorlhirig erinnere; to @haiti-'ge greatly Titi,

teo

when changing the system "fromK normal working to McCulloh working, or vice versa,

and so. mighgive rise to various troubles. To obviate this diiiculty I provide special non-inductive resistances 31, one Ifor each such grund return circuit, which are of higher value than'resistance 30, to. compensate for the exclusion of one of the relays 9 and 10 from each ground return circuit; and I provide circuits, and o n switch 13 contact-s therefor whereby resistance, 30 is in the line circuit during normal working, and ,one of theseresistances 31 is in one ground return circuit, and the other resistance 31 `is in the other ground return circuit, in Mc- Culloh working. The circuits controlled by switch 13, by which resistance 30 is thrown out and resistances 31 thrown in, when changed from` normal to lvIcCulloli working, will be readily seen'in Fig. 1. In practice these resista-aces 31 are-of about 9000 ohms each; (it being understood that the values for resistance, referred to throughout this specification, are approximate,`and are subject to variation in accordance with different" operatingY conditions). On the alternating current side of the receiving apparatus, a similar larrangement of resistances is employed, the normal resistance 32 being arrangedA to be thrown out of circuit when the switch 28 is shifted for McCulloh working, and other somewhat greater resistanccs 88 being included, one in each of the ground return circuits thereby produced.

rIn order to compensate for the decrease.

in inductance ineach ground return circuit, as comparedvwith the induetance in the lmetallic circuit, due tothe exclusion 'of one orv the other of relays 9 and 10 from each ground return circuit ofthe direct current system, the inductance coils 7 at thereceiifing end of the direct current system are soA arranged that an additional inductive value is added to each coil when the system is operating as two ground return' circuits. This is accomplished by providing the coils 7 Awith separate windings, 7a and 7b, of which the two windings 7 only are in circuit in normal or metallic return Working, but when switch 13 is shifted for McCulloh working, windings 7b are thrown into' these circuits by the vswitch 13, each ground return circu1t then including one Winding 7n and one winding t This arrangement obviates-the greater leakage of alternating current through thedi-4 rect current side which would otherwise occur during McCulloh working, without in lcreasing the inductance o1' the direct current system during normal working.

b connected in series.v

one is served by relay 9 a/nd register 11 and the' other is served by relay 10 and register 11. In like mannenshould a break without ground occur in the phantom circuit 17, the armatures of relays Qtand 95 will drop and signal receiving devices 26 and 27 will-operate continuously instead of intermittently as in normal operation; and thereupon the attendant will reverse switch 28, which has so l the eiiect of converting'lthe phantom circuit, y

or alternating current system into two independent ground return circuits. Should the break-occur in conductor 1 or conductor 2, the armatures of all the relays 9, 10, 24 and 25- will drop, Vand .the attendant will reverse both,switches 13 and 28. Should a ground occur in the circuit 4 or inthe circuit 17, this is evidenced at the central station by fthe operation of the signal receiving device 19, (in case circuit 4 1s grounded) or by the operation 'of' receiving device 9.7 (in case cirlcuit 171s grounded) and thereupon the attendant will not onl.y.reverse switch 13 or switch 28 thecase may be, but will also reverse the so-called McCulloh switches 29 on the relays 9 and 10, or 24 and 25,as.the case may be, so that said relays then work vthrough their back contacts instead of through their front contacts as formerly.

It the ground should occur in one of conductors 1 or 2, `the operator will reverse both switches 13 and 28 and all .of the McCulloh switchesF 29. y

The following is a statement of the relative proportions, as to resistance, inductance, etc., of the various parts of a system such as shown in Fig. 1, which has 'been found to work satisfactorilyzOn the direct current. siderelays 9'.and 10 are each of about 1000 ohms. resistancev 30 employed in normal yworking is of about 7000 ohms and the line non-inductive resistancesl employed in ground return or McCulloh workin@ are each of about 9000 ohms. The, winding "l"L of the inductive resistances at the receiving end of the line are such as to develop an electromotive force of 450 yvolts when passing 2.5 milliamperes at 240 cycles'per second. The windings 7b are of such value that when the direct current side is working as two ground returncircuits, the total inductance in each v circuit is increased' to about. twice the inductance used in normal working, the inductance being then such as to develop 450 volts when passing about 1.25 milliamperes at 240 cycles. The 4coils 5 at the transmit- .The line non-inductive direct;.currentside so great inductanee as .to-

' siderably ond.l The inductive Prsistances"7L7 intese vting end of the direct current system, arel ed to proportioned to develop each amiiduclve force of from 3,16

electr-emotive force of 51:50 volts when' pass` ing 2.5 unllisinpercs et E240 cycles per sccarc designed with a view to developing the same inductive volti ing current, entirelyindependent of whether the direct current of the direct current side is passing through the Same windings or not, as otherwise a considerable interference be-. tween the direct cur-rent and alternating current side would be observed. These coils are therefore designed to operate et relalivel)7 low ilux densities; vthe flux densities being' held eir'gap in the magnetic circuit,` es Shown, This holds the permeability ofthe magnetic circuit practically constant. As a result the inductive values given above are practically independent of the passage of direct 1eurrent through the coils up to the value of 20 mentioned.

milliamperes,wl1ich is much above thexvorking value of the direct current used in lthe system described (such 'Working velue being say about 8 milliainperes). y Thesefeoils "a-Jb and 5 moet have such i alue that on ,the one hand', they will. reduce to e moglie glble value-the leakage of alternating .current yto the' direct current side, 'end on the other'hund, they will not introduce into the' too greatly retard ,the rapid current chenqes met with in direct current signaling.y r,he

coils of the values labove given meet this und there considerable leeis to sity the coils may have conH less or considerably greater `i11 ductaueeizind still permit successful operocondition, way-that tion. i

On the alternating lcurrent siddthe line' resistance B2 used in noi-mel Working, 1s usually' of uboot 3100 ohms resistance, end

Vthe resistentes 33 used in McCulloh Werl;-

ing are usually of abouty 7600 ohms. AThe condcnsers 18 and 21 on the alternating side are necessarily small, their maximum value' being determined by the leakage current due posed upon .them by to the pulsating; direct current potential imthe operation Iof the d'1- yrect current side of the system, The minimum ,ensei-s is dictated by the high potential required to force alternating current 'through conde'nsers of low value. Each oftheseslternatiog current line con- .densers has a value of .03 micro-fared, and develops an electromotive vtorce-Lot 308 volts when passing i current ot 2() milliamperes Condensers 21 ure each used mconnection with on adjustable inductance eoilQQ which reduces the electromotive-for'ce to 1G volts when passing 2G ulilliamperes M240 cycles per second. Condensers 18 are euch used in connection with an adjustable Ainductsnce coil 19 'adoptand 5 e for e given alternat-k Lcoiudenser Y18 Should down by the introduction of eli 'erster of about 250;

'crater 23 should he driven 2O inilliamperes et 24:0 cycles per second,

l the inductive value ofthese coils depending upon the position of their sliding cores. it found in praeticqnec'essary to adjust the inductanee coils 19 Iio their purticulor coitdensergs und line conditions, 4when rst linsta-lling the system. In enersl, no further odjustment of these in acta-nce coils 19 required except in case the corresponding be replaced by t new condenser. .The relays 24 und 25 on the ,ulternating current side have o 'resistance euch of about 180 ohms and their coilshove such iiiductarice as to develop about 8O volts 'when passing 20 milhumperes'at 240 cyclesper second, The coildeusers ,34 used in servies with `these re ays are of from .l5 to .Qiniero- .fax-ads.; the effect of sucltcondensers being to reduce the combined potential Tto Iuboot 55. volts when passing the Torrent above x 'gli-he direct v,curregot used to operette the direct 'current Veide otthesyftatem, und defrvef fr Je @estetici 1.4, e a 110 .wir @Hrrnt, reread by the rese-*owe mentioned to about 2e ,tolte teresa the .line l and 2 where these wires leaveV the receiving station, and ,when thecircuit ,is closed. The Working current isobout 8 niilliamperes both on normolfigmd AlvlchjlHeh working.

The alternating current used to operate :the 'alternating currentside oi Athe system, hesyas above stated? requeuc .of 240 cycles nerseeond find c voltage :it the genareduced to about volts atcroes the liue'wieswhere they leave the stati-onen olosedcircuif The Working current `on ,the ynlterififititig current side is 20 milliamperes both ounormel and Mc- Culloh Working. t t

ico

ics'

Preferably theruifseruotiiig current Aeenat very consta-nt speed, as the etieetot' change( of speed is of course ,tochouge the frequencyof the alternoting current, and as has been explained heretofore, .the :various ,erwise slight changes in the voltage `of the direct current driving; the motorl generator set, 1.vill produce changes in speed yot' the set. To further reduce vthe probability lof slight changes in speed, the rotating. parts designed so :is to l of the set are customarily have a considerable inertia effect, so obviating changes Lof speed due to rapid changes in loed-., The gcnerator should be of euch parts of the systemfv 'tre adjuster. With respect Tto ,a ,definite freiso design as to give an electromotive force wave that is substantially sine in form and which does not material changel its folin forv changes in load. The generator field should be run -at constant excitation, as otherwise it is likely to disturb both the' speed and wave torni of the generaton Referring now to F igs. 4 7 inclusive, showing;` a special type ot' relay which I have found particularly eliective for use on alternating currents, designates a horseshoe electrofmagnct such as is commonly used in relays, provided with the usual adjusting de vice 36 tor moving themagnettoward and lfrom the armature. relay consists ot a` steel rod 37, ot such weight, stiffness, and resilience that it may vibrate in harmony with the alternations in the current energizing magnet 35. This ar mature is supported, at one end, by Athin `flexible strips 38, adjustably secured in clamps 39 ot a rigid support 40.' The relay Iis provided with front and 'rear stops, 4l and 42, of which both, in the construction shown, are Contact stops.' eyond these stops the armature is provided With a weight, 43, for regulating` `the period of normal vibration of the arimiture,i 'such' weight being, preferably, adjustable upon the armature, for which purpose the end porlionot the armaturefis screw-threaded and thetgweight is arranged to 'screw baci: and forth on thisportion ol the armature, 'and is provided vvitit'aA set screw 44, to hold it in any position to which it may be adjusted. The purpose of so ad- "justing the-'weight is to vary the normal rate. of vibration of the armature, when necessary, to correspond with the rate of Vibration'im-posed on the :tr-mature by the alter natingr current energizing the relay magnet:

' and when such',adjustment hasbccn effected .stop ll1 and provided with a source of current, will showV tar less than the proper strength ot current flowing, through such circuit: and as the adjustment of the Weight more nearly :niproaches what it should be, the burr/ling noise decreases and the voltmetcr shows rise in current, unt-illinally, when the correct :uljustment has been reached', the

huzzinr,r noise ceases completely, and the volt.` meter shows il'ull current atrenrth,Y the contact then els-tamed being. ais-'perfect as m an relay is not required. if

Thearmature of thisl ordinary relay operating' on direct current. ln extreme cases it may be necessary, for purposes ot' adjustment, to loosen theclamps 39 and adjust the lcng'tlro'f the strips 3S between said clamps andthe armature itself; 1 but in thc casix of a relay once properly adiustcd by the maker, adjustment of th length oit the strips P18 for slight variation in frequency of the energizing; current of the .i

ln operation, and supposingan altcrnati ing current oit' definite frequency to be assin'g through the coils of the relay, an( the f weight on the armature lever tobe insuch position that said armature is tuned to that'. `.lh frequency, the armature will be against its I front stop 4i, :1s-indicated in Fi". ,5, and will vibrate about such stop as a nodal p0int. It has been found by experiment that the greatest motion of the armature vis at its lipper end, the flexible strips 38 permitting. free motion of the end of the armature while at the saine time supporting it. Since the"` 'stop 4l is at the nodal point of vihration,-t the contact vformed by the armature with thi stop is as perfect as in an ordinary direct current relay. The armature therefore responda a., .to-breaking and closing,r of the alternating` current circuit. in the same way as the armal A, turc of an ordinary neutral relay responds il to tlu` breaking and closing of a direct ruwl rent circuit; and the armature of this` alter- ,"nating' current relay does not leave its fron stop during the intervals of no-magnctiznvtion incident to the passage of an alternab i ing current through the coils of the relay magnet, as would the, armatureof an ordinary relay, but remains in contact with itl, l stop during the intervals of current reversal,

heeause this stop is at a node, and the peri l odic 'vibration ot the armature is then morde` ellcctive to keep thcY armature .in contact f with its stop than is the retractile sprintf 45 to pull the armature asa Whole away rom Y said stop. If, however, the alternating cur- 11?' rent passing through the magnet coils of the relay is of a frequency materially different from that frequency to which the armatml is tuned, then although the armature may bl attracted upon the closing of such alternat ing current circuit, and ma be retracted upon the breaking of such circuit, the cone tact between the armature and the frontstofajI 41, is not sufficiently goed duringclosed cir* cuit intervals, to pass current through suck* Contact to a material extent; for 1n auch case the node of vibration, if any, ofvtlw armature is not opposite the stop 41, anni therefore saidv armature is continually clos ing and breaking contact with such stop, during the closed circuitintervals, the com' tact of closure boing too brief to permit mlterial rise of voltage while the contact exists, The relay shown is therefore in effect irre sponsive'to currents of frequencies other gemme than that to which it is tuned, bli com! pletely respnnsie to .Gurients of the fre- Vqueney to which it is timed.

In Figs. 8 and Q l iilnsi'ee im alternative' ferm of this relay, similar in principle t0 the form shown in Figs. 4f? inclusive,

but, having certain practical operai-ive eil-- ventages. In this i'erm, the armature instead of being provided with e tuning Weight B, is provided Witli'e peddle 426 adapted to move backward and forward in:

fluid in :i @up 47, this cup being adjustable vertically by 'means of mrew threads, es

sliowmie varyilie depth (if immersion Gif' the peddle and, ceusequeniy, te vary lie` resistance oll'ereil to ilie malien of the perl. 'die Thls construction lies tlieedvimtage that julie relay may be tuned to dierent freuencies While in operation sind Without,

'c leaking the vibretieii ef elle ermeure,

is also eim this reley le semewliet' easler e adinet lien is the "Weight form of rel-ey shown in Fig. @wie olier Wercls, it e eeniewhe't ge/eater working margin. This rliiereiiee is prelueiily due fe tiie ieee he; She liquid imei-poses e fired l reeisense te lie vilnreiee ei eline armature, wlw, as elle Weigh. 3 el Fig. i 'iiierpeeee 'ey er Y.

irest :L live meistens@ lie elle mel-ien of` the ernmure. l

ln ille description of itl`ig-.-.l i line been assumed that the receiving relays 2li and eI" lie alternating emrenl. eystem villerein illustrated, are of e iype specie-Hy adapted to werk with alternating currents, end pfeil 1 erebly the type illustreefl in Figs. f-9 in# elusive. It is possible', lieefever, in meiiyl enses, to use ei'iinery relays in )lie :drei-me fermetures egeiiis-tlieir cosiiecla stops owing to theintermitteu action of lle elerieting currentend consumi: change ef polarity flue te the 'eentent reversele of suoli current. One meljliod of eilepting ordinary relays te use en elle elevmeeing cement, is illustreezl in Fig. 2, in which, in connecicm Wili each,

of the receiving relays, here numbered 24 ,und 25, e current rectifier iilusteed clim grammetlcally al; 9.4", and 25,.-i'e employed.

I do not limit myself lso mjy paiftvieular ype of rectifier .bei lieve-found e ireeeell slee trolytie reelgllier ef Well knows. type, mclicated diegrammaticfrlly in Fig, 2, -e ne ef-j festive. Such rectiiiers ere'well k'llinevi'n axial do noi; require deteil description here, E have found it conveieiit in such reeiiieislo use iron and aluminum eleetrofies uml to use eleetrol te com @sed of l )art berai, 2 Y ertsr concentrated ammonia, 4 paris bari@ ecicl and 128 parte distilled Walt-er. At low fre quency (up te GO cycles per semind) lie maintenance of tlieee reC-iiiers is met excessive und iieir performance is fairly een; stent. 0n higher frequencies, however,

Fifi

their main tenanee veel', becomes grenier and their perimmeziee ie not Se sneieieutery. Since ier ecoiiqmjf, i e first ees?. el iler app mme, it, iskleeirehle te use e mueii iii!" frequency ilxeu (l0-cycles, l du zum er eerily prefer te use the arrangement, .shown in F il, invelving ille use. ol' the weiiers. it will be uncierstoecl that ne eiiert lke?? the reetiiers 'e0 supply current of one. clirection io the releye 24 wml 25, notwi imding that he current supplied te the reeulers is im alternating current..

My inventien is not limited to the use ef n Single alternating eur-reni or phantom sysiem ilrcoimectien 'willi e direct ciu-rent', system ei treiiemiseien, but there may be a.. plurality of alternating current systems?, eperati-ng upon currents er different frequencies, and indeed, it is practicable 'te' operate a large number of different eliter- Helling curi'eii systems @ver the seme line Wires, with er wihout a direct current System else transmitting ever euch Wires.

in Fig. l lieve illustrated n. system similer ite thai shown in Fig. l, except that' liei are fw@ eleineing eui'ren receiving jene rimsmiing eels exa-Gili: Similar t0 'geeeli nl'lser verve-pl, flmt they 'effu'lr upon uuri'enee lii'ieiei'it frequency. in this (.lreW- ille seme :lr-,ference numerals ere used les in Fig. l, except that the numbers of the lsecoinfl elfe/meting current are disgtinguishecl from the numbers of the first :ileifneing current syslem by 'prime-merke; Furthermore, my invention is not limiized te use in district telegraph systems mici the lilie, but mey be eiipleyed inn ordinary 'te- "legeeinjv, l 'lll elmws v:l tele@ ieg ,three transmilt eliiee corresponding re emi 53, operatin e er mit 5. Transmiller and receiving relay 5l reeeive current from direct current gen. eretor 55 and ere ieelaed freni, fue alternating currents ef the other tl'ensmiiiereibjf 'inductivereeistzmee Tr nsmitiers 49 ami 50 sind lilieir eerresjpfming; reeiviiigg releys 52 and epereiie alpen alterneting eiirreiii: received from dieren-ting 'current gezieretere 5'? aml 58 reepeeaively, siiee'igeerators being 0i liile'rem; #frequeleiee,V En active resieeiiee 5.33 and e eoneiiser. Si'. isolates elle trnilemiiei e9 from em'renie f* frequeneies other tli'm @het ef generate? 52', 'sind inl similar meneer relay 52 is iseleed by inductive resistance el emi e eerlcenser 62 Treeismilsee'() similgwly iselsieclby.. inductive reeieteiiceS-' enel a, eei'idensje 64, :md iis relay by imlueive resieleiiee Gfaml a 'cenclenser 66. lty will ne seen 'liejif iii tliie errengemen @eeh iraesmi-eexf emfilitsfcer respmiclim'; receiving relay are coiirieeecl te die `line lzhrexiigli' .ieeleirlg means which im- "apli eye-teni ei'impriS- sind` poses' r'eleively smell resisienee` te the par me so at the distant end of the line.

ticular current upon-'Whichthat transmitter and A, receiving relay operate, but .imposes` very great resista-nce to the currents upon which the other transmitters and receiving relays operate.

Fig. 1l shows an arrangement siniilar to that of Fig. lft circc'pt-that'two ot the transmitters are arranged to 'transmit in one direction, and a .third transmitter to transinit in the opposite direction over ,the line circuit. It isinimateri'al Whether all of the transmission' systems ot F l0 and'll ltransmit in the sanie direction or Whether some transmit in one direction and some in the opposite direction.

- F ig. 12 illustrates an arrangement' similar to those of Figs. l0 and 1l, except that the various transmitters and receiving relays are located at diilerent points along' the line circuit.

I may also duplex alternating current Y systems such as hereinbeore described, accordingn to the Well known systems of duplex 'telegraphy, so Athat transmitters using Icurrents'of the saine' frequency or characterv may be located at both ends' of a line, the transmitter at either end of the line having no effect upon the receiving relay at that end of the line but affecting onl the relay `)ne duplex `circuit arrangement is shown in Fig. 13, whcrein at the twoends or the line there are alternating current generators'? and 68 respectively, andvtransmittcrs 69 land 70Y respectively.

,71 designates the linelconductor, 72 and T3 designate repeating coils at the end, of

vsuch line cond' ctor and between the line conductor and lthe corresponding transmit 40 -ter, Tt and 7 designate artificial. lines, and

- 76 and 77 designate receiving relays induc-l tivelyv connected to the line circuit through the repeating coils '72 and 73. 7S and 79 designate.- respectively, adjustable inductance coils in the stai'icns at the 'tivo ends ofl` the line :tor liaiancing the line induo tivelv and 8() desiifnates line resistance. lt`

,Will'he obvious.;y .that the outgoing current at'each end of the line divides, in passing l 5o thrpugh the repeating coil, 79. or 73, the currents inthe-two sides of such coil neutraliz inlg each other so that there Iis no inductive eli'ect upon the home relay, 76 or 77; out that at the distant end el* the iinethe ineenling' currents pass through the line Wiud- Y ductanceoi" the direct current circuits is a V posed lobtain alternating' currents of. definite and tcrnati'ng" current from the direct current bodying ,rny invention,'of sources of supply of alternating current adapted to supply current of substantially constant frequency, is an important feature of my system, bc' cause since the inductance and capacity of the alternating current circuits and thein justedA with respect to definite frequcncie material change in .these frequencies beyon a certain limit7 calls for readjustment of in- 15 ductance and capacity, and if the source 4of current su pply be one which gives different frequencies at' different tim` s, such read- "ustrnent is obviously impracticable. `More over,l 'the alternating current relays e'mn' played in the systems other than thatshownl in Fig. 2, themselves require for working that 'they current hy which said relays are I. operated .shall be of substantially constant' frequency, for as stated, these relays do not make good-contacts `when t'heyiare not 'synchronizcd with respect to the current on which they'` are to be operated. Iam aware that heretofore various systems 'of alternating` current-transmission have been supcl'im` au. upon direct current systems, the nlternating currents in such cases having been obtaincdbymeans of induction coils and condensers, the transmitter closing andbrealringthe primary circuit of thc' inducf` u' tion coil and so producing inthe secondary or line circuit a current pulse of one direction upon the closing of the primary circuit, and producinga current pulse of the oppo` site directionin the secondary circuit uponk my the breaking of the primary circuit. Obviously it is impracticable in such systems to constant frequencies, and therefore it is iml practicable in such systems to proportion in- 10g., ductance and capacity with respect to a de-y nite frequency.

'What l' claim is d 1. A multiplex telegraph system comprisf, ing in combination a line conductor, a direct nii current generator, a1 constantly operating al` ternating current generator adapted to supply alternating currentof definite 'and substantially constant frequency, a direct current transmitter, direct .current receiving n; means, inductive resistance interposed be-. tween said direct current transmitting Vand receiving -Ineans and said conductor, and proportioned with reference-to the alternating current to substantially exclude such al- 1 transmitting and` receiving means, an alter' 'hating' current transmitter and alternating current receiving' moans, and. condenscrs and inductive rcsistanccsinterl' ed between said 135'; i

tierY rent to sr but to substantif rality of Leases/1 the direct current from the alternating cnrrentI tra-usmitt-ing` and receiving' means, said alternating' current transmitting and receivingr means and alternating' current zgenerator and their corresponding condensers and inductive resistaiices1 connected across the circuit comprising,V the said line conductor and the direct current transmitting and receiving means', L( {cncrator and inductive resist:- ances7 said4 alternating` current receiving means comprising; a relay having' a vibratory armature timed to vibrate in harmony with the current reversals of the alternating current and arranged to cooperate with a contact located substantially at a nodal point ot said armature-when the latter is vibrating in harmony with such alternating' current.

i?. A multiplex telegraph system comprisinnl in combination a line conductor2 a pluconstantly operating alternatinll current generators each adapted to supply alternating currentot denitc and substantially constant frequency, the frequencies ot said 4generators being different With respectto one another, a corresponding plural-ity ot altcrnatincT current transmitting and receiving means, and condcnsers and inductive resistanee` each set ot',i,iaiismitting and receiving; means proportioned to pass freely alternating current ot' the Jfrequency pertaining; to that transmit ting' and receiving means but to iositively exclude alternating currents ot di erent` frequencies., each such receiving' means comprising' a relay having' a vibratory armature tuned to vibrate in harmony with thc corresponding alternating' current and arranged to cooperate with a contact located substantially at a nodal point of said .armature when the latter is `vibrating 'in harmony with such alternating Current.

C-. multiplex telegraph system comprising' in combination a line coiuluctor,- a plurality of constantly operating alternating current gcnm-alors each adapted to supply alternatingn currentot' detinite and substantially constant frequency, the frequencies of said generators bein-e; diti'crent with respect to onel another.y a corresponding plurality ot alternating current transmitting and receiving' means, comprising!` condenscrs and inductive resistance, which are proportioned, tor each set ot' transmitt-ing),` and receiving means, to pass freely alternating current ot' the treqi'icucy pertaining-to that transmitting' and receiving means but to positively exclude alternating' currents et'` diti'erent'frequent-ics. rai-li such receiving means comprision a relay having a vibratory armature tuned to vibrate in harmony with lthe corresponding' alternating current, and arranged -tc cctpcrate with a contactlocatcd substantially at, a nodal point of, said armature when the latter is vibrating; in harmony with such alternating current.

f. i. s. A multi lex vteleefra Jh stein com )ris-Vv t in g, -in combination a line conductorE a plu-v ra'lity ot alternating current `generators ot dilierent frequencies respectively, each adapted to supply alternating' current ot a definite and substantially constant trequcicy` a plurality of alternating current transmittiiig and receiv/ing means, a condenser and inductive resistance interposed between each such transmitting means and sa id conductor, and proportioned with ret'crence to 4the alternating current frequency correspendingl to .that transmitter and receiver te pass freely' alternating current-vof that, frequency, but to sul'istantially exclude altermating currents of diiterent frequency, and a condenser and inductive resistance interposed between each receiving; ii'ieans and said conductor and proportioned with reference tothe alternating ycurrent to which that receiving means is to respond, to pass freely alternating current of the corresponding sol frequencies but te substantially exclude alternating currents of different frequencies,' each such receiving` means comprising a relay having a ribratjory armature tuned to vibrate in harmony with the alterirating` current of the corresponding frequency and arranged to cooperate with a contact llocated substantially at a nodal point ot said armature when the latter is vibrating in harmony with its corresponding alternating W current.

5. iii. multiplex telegraph systein'ccmprising inciuubination a directJ current signaling syste/mand an alternating curi'cntlsigmaling system, said two systems comprising a common line conductor, the alternating current srsten-coin n'isinnr a source ot su n,

.i n v ply ot' alternatiug Y current ot' definite and substantially constant frequency, and conipris'ing also isolating means.proportioned to substantially isolate such alternating current system from the direct current, but to transmit the alternating current *ciyvr the direct Vcurrent system comprising;l a source ot' supply of direct current and isolating` means proportioned l to substantially isolate such direct'current system 'trom thc alter- Hating current, both the direct system and the alternating*current system comprising large nhinic resistance proportioned to make the line impedance due. to resistance7 the controlling factor of the total 'line impedance.

6. A multiplex telegraph system' comprising' in combination a direct. current signaling system and an alternating current signailing" r'iystcniA` hotli said systems heine'A norrent system" from the direct current7 but t0 transmit the 'alternating current freely.) tllie direct current system comprising- :t source of i supply of direct current und isolating" ineens' 'proportioned to( substantially isolate suoli direct current sy tem troni the alternating current, both tlieldircct current system and the alternating current system adapted for 1U McCulloli operation and cemprieing line McCullolx switches whereby either suclr sys. ltem muy 1ceconverted-intc two independent systems?tiend- `'comprising elec seperate re inceiving means for catch such independent system, suclrdirect current system further comprising e large ciimic resistance .includec't in circuit by' ldcflulloln switch when that system is operated es. e inetnllic returny System, und further comprising other olimic esistencee arranged to be included in the iudependent circuits seid McCulloh switch, duringllflcCulloli operation, eueli further re# sistcnces of value adujo-ted tu compensate 'for' the absence in 'cach of tlie'intiepcndent 25 tems during; l/lcCulioli operation of one of 'the two receiving ineens included in the circuit during normal or metallic-circuit ener ation. f

Y. A multiplex telegraph c" 3o ing in combination. e direct current iing and en alternating current eig l nailing System7 lietli, seid Systems bei/ng' normally metallic cir-cuit systems nml comprising tne seme line conductors the alternating current system comprising zt source of? @upn ply o1 terneting current of definite and sul'etentieily constant frequency, and cornprieing ilse isolntinglineene proportioned to substantially isolate auch alternating cui"- lio 'rent system from, the direct eurrei'it, fout to transmit the alternating current 'reel tne' directcinrei-it system comprising' e source of 'supply of direct current n" isolating ineens proportioned, to substent Yly isolate such direct current system. from. time alternating current, both the direct current system end ytliealternating; current syetein :Adapted 'tor Mc"'uilo`nI (poration und cnn-)rising line ltlcCulloi-switclies Wlie 'eby'eitlicr suoli sys l tem muy lie converted into two in en ident systems, and comprising also scp e rccciving ineens i'or mieli. s'ucli independent system, Such alternating current system i'urtlier comprising t large olnnic res- :tence ineluded in circiiitbytlec ticlulloli ,sv-:itch 'when that system is op ed ne u. metallic return systeni, and furthe comprising other climi@ resislnnccs m'rnnnjml io lie included in tlicA inclencude" y circuits lig." seid ll/clulloii SQ svvitctiwlurixig McCulici'i opcrntion such fur- Ntlior reeist'zmccs oi: velue adept to comH pensate Ifor the absence .ir L" tlie. 2ndeu pendent, systems du included of one of dtlm twc rc,

meneer in the circuit during'normal or metalliccircuit operation.

8. A multiplex telegraph system Acompris-` ing'in combination tWo alternating current signaling systems, both rscid systems being normally metallic circuit systems andcomprising the same .line conductors, the two systems comprising each e source of supply of alternating current of definite and substantially constant frequency, but quency dilierentfrom that ofthe other systeni kand comprising Lalso isolating means proportioned to substantially isolate such' system from current of 'the frequency of the other system, but to transmit its own alternating current freely, both seid systems adapted for McCulioli-operation, and comprising line McCullcli switches whereby either such system may be converted into two independent systems, and comprising also separate receiving ineens for euch such independent system, each such system further comprising a, large olimic resistance includedin circuit by itslVlcCullohswitch Awhen ,that system is operatedv es e metallic return systemj endgfurtller comprising othercliinic resistencias arranged to be included in the independent circuits by said McCulloh switch during McCnlloh operation, such further resistences .of value adapted to compensate for the absence in each of the inde-v pendent systems during McCulloh operation of one of the two receivingfmeans included in the circuit during normal or metalliccircuit operation.

A multiplex telegraph system compris! ing in combination a direct c rrcnt signaling ,jy/stem and ein clteri'xuting current signaling system, both said systems being normally metallic circuit systems, and coi'nprisingl the Same line conductors, tlie :.xlternet'ing current system comprising a. source of supply of alternating' current of definite und substantuilly constant requency and connorisingi;l also isolating means proportioned to -substmitially isolate Such4 alternating current' system from the direct current, but to transn it the alternating current freely, the direct current system comprising n source of supply et direct current, both the direct current system and the alternating current systeni :1de ted for McCulloli o )eration end P l' i comprising line McCullo-li switches whereby' eitlier such systcminay be converted into two imlependent systeme, und comprising also separate receiving means foreach such independent system. such direct current sysf tem turtlxer comprisimg iifiductive resistmiccs controlled 'ny tire direct current McCullohewiteli and arranged to lie included in 'the metallic circuit during normal operation and in euch. independent circuit during Mc- 'fiiili compi isinrg 'further ilrewise izontrolled by A uw' Mcounoh Switch and. 'arranged to be ineluded in the independent circuits during McCulloh operation, such additionalinduo tive resistance proportioned to compensate for the 'absence in'eaoh of the independent circuitsl during McGulloh' operation of .the inductan of onev of thetwo receiving means included in the circuit during normal Aor metallic circuit operation, the said inductive 4resistances on the direct current system provportioned to substantially isolate such direct v4ply, proportioned tothe corresponding ourrent frequencies to pass current of that frereceiving instrumentsench corresponding to quency but to exclude currents of other frequencies, and a plurality of synchronized one of the current frequencies of the system, and synchronized to respond to current of that frequency, und isolatinglmeans for each such lreceiving;y instrument proportioned to thecorresponding current frequency but to 'exclude currents of other frequencies,

11. A' multiplex 'telegraph s y'stelii-eo1iiprising. a plurality of alternating current systems, operating on different frequencies, over the sameline circuitvand each having transmitting and receiving means -located in line sliunts proportioned as to inductancc and 'capncityto pass currents of the corro l spending frequency, but to Aexclude currents of` other -`frequenojies, said receiving Y.means each synchronized. to'respond effective to eurrcntsofits vcorresponding,r ,frequency only. In`test1mony whereof, I' aiiix myslgnature, in the presence vof two'witnesses.

' Jos'ErH F. n noon.

Witnesses:

Y M. M, Trione, CHARLES F.. PA'rrERsoN. 

